Question

What is meant by 'Southern Oscillation'? State an important feature of it.

Answer 1

(i) Usually while the tropical eastern South Pacific Ocean experiences high pressure, the tropical Eastern Indian Ocean experiences low pressure. But in certain years, there is a reversal in the pressure conditions and the eastern Pacific has lower pressure in comparison to the eastern Indian Ocean. This periodic change in pressure conditions is known as the Southern Oscillation.
(ii) An important feature connected with the Southern Oscillation(SO) is the El Nino, a warm ocean currnt that flows past the Peruvian coast, in place of the cold Peruvian current, every $2$ to $5$ years. The changes in pressure conditions are connected to the El Nino. Hence, the phenomenon is referred to as ENSO(El Nino Southern Oscillations).